Apparatus for producing heaters for plural purpose vacuum tubes



Oct. 6, 1964 H. LEVINE 3,151,637

APPARATUS FOR PRODUCING HEATERS FOR PLURAL PURPOSE VACUUM TUBES Filed Sept. 28, 1960 4 Sheets-Sheet 1 INVEN TOR. /%evi,v Air/M'- Oct. 6, 1964 H. LEVINE 3,151,637

APPARATUS F OR PRODUCING HEATERS FOR PLURAL PURPOSE VACUUM TUBES Filed Sept. 28, 1960 4 Sheets-Sheet 2 INV EN TOR. fifm/iy div/A2.

Oct. 6, 1964 H. LEVINE 3,151,637

APPARATUS FOR PRODUCING HEATERS FOR PLURAL PURPOSE VACUUM TUBES Filed Sept. 28. 1960 4 Sheets-Sheet 3 "WWW INVENTOR. 194m ZiW/YE Oct. 6, 1964 APPARAT FOR PLU Filed Sept. 28, 1960 H. LEVINE FOR PRODUCI VA PURPOSE 3,151,637 HEAT M TUB 4 Sheets-Sheet 4 United States Patent 3,151,637 APPARATUS F832 ZRQDUCENG l' EA'ItERS PLDIRAL VACUUM TUBES Harvey Levine, North Arhngton, Ni, assignor to Radio Corporation of America, a corporation of Delaware Filed Sept. 28, res-s, Ser. No. 59,1) i4 Qlairns. ((31. Mil-3&5)

This invention relates to an apparatus for producing continuous, one piece, gap-type heaters for vacuum tubes having a plurality of cathodes, and more particularly to improvements in gap-type heater spade winding machines.

Many plural-purpose vacuum tubes contain a plurality of cathodes, each comprising a cathode sleeve, each cathode being heated by a heater wire comprising an insulated resistance wire mounted within the cathode sleeve. The resistance wire from which the heaters are made is supplied in long, insulated, integrally formed lengths, and portions thereof are cut off and are bent into required form for inserting into the separate cathodes of a pluralpurpose vacuum tube.

The automatic spade winder used to produce the separate heaters comprises a rotating winding head from one end of which two spaced parallel blades extend and on which a wire gripping means is provided. The end of the heater wire is held in the gripping means and as the head, mounted on a power-driven shaft, rotates, the heater winder is fed so as to be wound on the blades in a helical manner. After a pr determined number of turns has een formed, automatic controls stop rotation of the winding head and the wire is cut oi, the insulation being simultaneously broken off and stripped from the ends of the Wire. T he blades are then moved towards each other to a collapsed position to permit an operator to remove the completed heater from the blades. The heater so produced is a complete heater for a single purpose tube. The use of such a heater to produce a series heater LOT 21 plural-ourpose tube, therefore, involves, besides the pro duction of the individual heaters, the extra steps of welding the connector between the ends of the heater.

It is therefore an object of this invention to provide an apparatus for winding continuous gap type heaters for plural-purpose vacuum tubes.

It is a further object of this invention to provide an apparatus for automatically winding continuous gap type heaters for plural-purpose tubes, the apparatus requiring a minimum of skilled attendance.

In accordance with this invention, the winding head of teh automatic gap type heater spade winding machine is provided with three spaced winding blades movable toward and from each other. An initial portion of heater wire is wound on these three blades. Two of the blades are longer than the third. A subsequent portion of heater wire is wound around the extended portions of the longer blades. Other means are provided for moving the blades closer to each other after winding than they are during the windin step, so that the completed heater may be stripped from the blades on which it has been wound.

This invention may be understood upon reference to the following detailed description taken with the accompanying drawing, in which:

FIG. 1 illustrates a heater made by apparatus made according to this invention;

FIG. 2 is a side elevation of the winding head portion of the apparatus made according to this invention partly in section and with the side plate broken away, showing the winding blades in their collapsed position;

FIG. 3 is a similar side elevation of FIG. 1 the winding blades in then winding position;

FIG. 4 is an end elevation of the winding head shown in FIG. 2 with the blades in collapsed position;

showing FIG. 5 is an end elevation of the winding head shown in PEG. 3 with the blades in winding position;

FIG. 6 is a side elevation of a heater winding apparatus with the winding head shown in FIGS. 2-5 inclusive, in position and showing the means for actuating and rotating the winding head as well as the means for feeding wire thereto and the means for removing insulation and for cutting the wire;

FIG. 7 is a section taken along the line 77 of FIG. 6;

FIG. 8 is a section taken along the line 8-8 of FIG. 6;

FIG. 9 is a fragmentary plan View of the apparatus shown in FIG. 6 and showing the relative positions of the insulation cracking and wire cutting means, the heater wire feeding means and the winding head;

FIG. 10 is a plan View of the insulation cracking and wire cutting arms in open position;

FIG. 11 is a plan view of these parts in closed position;

FIG. 12 is a section on lines 12-12 of FIG. 11; and,

FIG. 13 is a wiring diagram and schematic showing of the controls used in connection with the apparatus made according to my invention.

FIG. 1 shows one form of gap-type heater which can be wound by apparatus incorporating this invention. As shown by this figure, the heater wire 14, which comprises a resistance wire 16 covered with insulation 18, is bent into the form shown by the apparatus of this disclosure. At the sharply bent portions 20, the insulation 18 may break away since the insulation used is relatively brittle. At the less sharply bent portions 22, the insulation may remain. At the legs 24, the insulation is broken away after the wire is wound and just before it is severed.

This apparatus includes a frame which rotatably sup ports the winding head on a power-driven shaft. The winding head is supported at one end of the shaft and the other end of the shaft is connected through a magnetic clutch to a power apparatus.

A wire guide and feeding mechanism is supported on the frame adjacent the winding head and is mounted on a slidable support so that it may be moved parallel to the winding head during winding operations. Movement of the wire guide and feed mechanism is accomplished by means of a rotating cam connected by a gear train to the power-driven shaft upon which the winding head is mounted and contacting the slidable wire guide and feed support.

A crack-off and cutting mechanism is mounted adjacent the winding head and between the winding head and wire guide and feeding mechanism. This last mechanism comprises a pair of jaws moveable toward and from each other. These jaws are pivotally supported on the frame and controlled by the mechanism mounted on the frame.

Mechanism is also provided for moving the blades on the winding head to open position and to collapsed position. This includes a cam driven from the shaft supporting the winding head and a bell crank mounted on the frame, one end of which contacts the cam and the other end of which is coupled to a cam mechanism within the shaft supporting the winding head. This last mechanism contacts the blade assembly.

Control switches are mounted on the frame to control circuits for controlling operation of the various elements of the apparatus in proper time sequence.

As shown in FIG. 6, a winding head 23 is mounted on one end of power-driven shaft 24-. The shaft 24 is rotatably supported on and projects in a horizontal direction from the supporting frame 26. The opposite end of the shaft 24- is connected through an electrically operated magnetic clutch 38 which is coupled to the motor and speed-reducfion device 36. When the clutch is energized, the shaft 24 is coupled with the continuously operated motor 36.

The wire feedin means 23 is provided for feeding 7 spring 68.

arenas? tends in a horizontal direction through frame 26.

The means for feeding the heater wire to the winding 'head comprises a pair of guide wheels 62, one of which can rotate only forwardly and between which the heater wire is drawn, and wire guide 64. 7

While feeding wire to the winding head 23, the feeding means must move to the right as shown in FIG. 6. To provide this motion of the wire guide and feeding means 28, the shaft 30 on which the feeding means 28 is supported is' slidably, but not'rotatably, mounted in frame 26. The shaft 313 is pushed to the right as shown in FIG; 6 by cam 66 upon clockwise rotation thereof and against the urging of spring 68 which is stretched between a pin mounted on frame 26 and a stop mounted on shaft 30. The cam 66 is rotated clockwise about its axis by gear mechanism 80 and shaft 44 coupled to the drive shaft 24 by means of gears 49 and 42. Thus, as shaft 24 rotates cam 66, the shaft 30 gradually moves to the right until the end of the shaft rides off the high part of the cam 66.

V The shaft is then pulled'back quickly by spring 68. This movement also controls certain circuit control mechanisms which will be later described in detail.

A crack-off and wire cutter assembly 32 comprising a pair of moveable jaws for cracking olf the insulation at the ends of the wound heater and for cutting the wire is also mounted on the frame 26 by means'of the support 34. The means for operating the insulation crack-off and wire cutting means 32 is mounted under the frame 36. The details of this mechanism will be described in detail below.

As briefly described above, the winding head made according to this invention includes three winding blades extending from the winding head. The blades can be moved toward and from each other by mechanism mounted on the frame. This mechanism'includes a cam 46 mounted on the gear 42 (see FIG. 8) 1 and the bell crank 48 (FIG. 6) biased against the cam by means of the spring 51. The end of the bell crank 48, which is pivotally mounted at 4? on the bracket 48' mounted on the frame 26, is provided with a pin 54) which co-operates with a groove 52 in a slidable collar 54 in turn connected to a cam shaft 58 (F168. 2 and 3) within the drive shaft 24. The cam shaft is operatively connected to the winding head 23 to operate the blades. The details of this mechanism and the co-operating blades will be described right, as shown in FIG. 6, finger 72 releases switch 76 permitting it to close. Similarly, as shaft is moved to the right, the pivoted'finger 74 rides over the switch 78, but this finger 74 causes closing of switch 78 for a short period of time as the shaft 39 is pulled to the left by 'Reference'is now had to FIGS. 2, 3, 4 and 5 which 'show the details of a Winding head made according to my invention. V

a The winding head 23'comprises a housing 32 mounted for rotation on shaft 24 andhaving three blades 84, 86

' and 8 8 mounted'to extend from "one end thereof. A

wire holding means tl also extends from the end of the housing'frorn which the blades extend. Blade 84 is fixed in adjustable position to the housing. 82, while blades 86 and 88 are pivotally mounted on the housing 82, whereby parallel winding position as shown in FIG. 3. Similarly, wire holding or clamp means 9t) may be open when the blades are collapsed, or it may be closed when the blades are separated.

The winding head 23 which is mounted on the shaft 24 comprises the housing 82 having end walls 92 and. 94, a wall 96 and a cover plate (shown broken away). The housing 32 is fixed to rotate with the shaft 24 by means of the integral collar 199 secured to the housing 82 and having a set screw member 1% for fixing the collar on the shaft 2% to rotate therewith. The cam shaft 58 extends through an axial bore in the hollow rotating shaft 24 and is mounted for anal movement therein as noted above.

Fixed blade 84 is adjustably fixed to the housing 82 by clamping means 162. The clamping means 1% is adjustable on housing block 82 along slots 194 therein. The second blade 86 is clamped by clamping means 166 to lever 1% which is pivoted on housing 82 on the back wall 96 thereof by pivot pin 11%. The lever 108 also has a pin 112 projecting from the free end thereof. The lever 14% is bifurcated at the pivoted end thereof and bell crank 114 is also pivoted on pivot pin 119 and between the legs of the lever 16%. The bell crank 114 has an upper cam face 116 cooperating with cam shaft 58 and overlying the legs of lever 168. The bell crank 114 also has a lower bifurcated cam portion 118..

The third blade 88 is clamped as by clamp '120 to a lever 122 which is mounted for rotation on a pin 124. The pin 124 extends from end wall of housing 82. The lever 122 is retained on pin 124 by fastening means 126 and it is spaced from the end of housing 82 by the cooperating end portion of pivot pin 124. The'pin 136 is mounted in a direction parallel to cam 58 and extends through end walls 92 and 94. The pin 136 also extends through an axial bore in pivot pin 124 and between the legs. of bifurcated cam portion 113. The

pin 136 has ahead portion 145 at an extreme end thereof, and a stop 14% is adjustably mounted on the pin 136. A spring 142 mounted between the stop and the end wall 92 urges the pin 136 to the left as shown The above-mentioned bell crank 114 in FIGS. 2 and 3. is urged in a counter-clockwise direction about its pivot and against stop 140, by a spring 144 mounted on pin 136 and extending between end wall 94 and cam portion 118 of lever bell crank 114. The spring 144 is substantially stronger than spring 142. Therefore in the absence of pressure by cam 58 on the shouldered cam surface 116, the pin 136 projects'outwardly from the face of block 82 and beyond the end of pin 124 due to the cooperation of the springs mentioned.

When the winding head 23 is in its collapsed position, as shown in FIGS. 2 and 4, the blades 34, 86 and 83 are close together, so that the heater that is wound thereon may be removed therefrom. In this position of the winding blades, the wire clamp is open. is extended to' the right to release the end of the heater wire by leaving a clearance between the end of pin 124 and the end of pin 136. :When, during the operation of .this apparatus, thecam shaft 53 is extended to its extreme right-hand position, the movable blades 86 ahd 88 take their extreme positions and clamp 99 is closed since the button 146 contacts the end of pin 124 as shown in FIGS. 3 and 5. This change of position of these elements is accomplished by cam 58 in moving to its extreme right-hand position.

That is, the pin 136 In that positiomcam 58, by contact with shouldered cam end 116 of bell crank 114, rotates the lever 108 clockwise to its extreme clockwise position, moving blade 86 down against the urging of spring 132. The pin 112 on lever 108, by contact with cam portion 130 of lever 122, causes lever 122 to rotate counter-clockwise against the tension of spring 134. The three blades are now at their greatest separation. Also, the lower cam portion 118 of hell crank 114, in rotating clockwise compresses spring 144 and permits spring 142 to expand and to move pin 136 to the left, whereby button 14-6 on pin 136 contacts the end of pin 124 to clamp heater wire between button 146 and end of pin 124. This position of the winding head is shown in FIGS. 3 and 4. This is the winding position of the head.

As noted above, means are provided for knocking or cracking off the insulation from the end of the heater wire and for cutting it, after a series connected heater has been wound. This means 32 is shown in FIGS. 6 and 9-12. A pair of upwardly and outwardly extending oppositely disposed arms B and 156 are pivoted on frame 26 at 34. The right-hand arm 156, as shown in FIGS. 10 to 12, comprises a block 152 having flat top and bottom surface and a cut-away portion 154 in the left face thereof. The left-hand crack-off arm 159 carries a block 158 having shoulders 16!) and having a cutaway right-hand end 162. This block 153 carries on its upper face, a slide block 164 which slides loosely between shoulders 169 and has a slot 165 therein. Slide block 164 is urged to the right by spring 166 pressing between pin 168 fixed in block 158 and the end 170 of slot 165 in slide block 164. This side block 164 has a cut-away portion in its end. The cut-away portions in the various blocks and slide blocks are complementary as shown in FIGS. 10 and 11. As will be noted by reference to FIG. 12, the upper surface of the block 153 is in the same plane as the lower surface of the block 152. Thereby, as will be more fully explained below, when arms 150 and 156 are rotated about their pivots 34 towards each other, slide block 164 hits block 152 and slide block 164 is pushed back against the spring 166. A limited amount of rocking of the slide block 164 is permitted as noted above. As the arms continue to move towards each other, the blocks 152 and 158 pass by each other in cutting relation. This cutting position of the blocks is shown in FIG. 12.

In the operation of the crack-01f and cutting arms 150 and 156 they are caused to rotate towards each other about their pivots 34 and to strike each other. This means is shown in FIGS. 6 and 9 and comprises levers 172 fixed to the ends of shafts connected to levers 150 and 156 below the frame 26. These levers are fastened by links 174 to a piston rod 176 which is moved to the right as shown in FIG. 6 to close the crack-elf jaws upon admission of air under high pressure to cylinder 178, as will be explained more fully below. A spring, not shown, in cylinder 178 returns the piston to its lefthand position and therefore rotates the arms 150 and 156 to its open position as shown in FIG. 9.

The wiring diagram of this machine is shown in FIG. 13. A source of electricity is connected through two switches 76 and 180 in parallel across magnetic clutch 38. An air cylinder solenoid 182 is provided for admitting air under pressure, and permitting exhaust thereof, to cylinder 178. This solenoid is operated momentarfly by the action of arm 74 on normally open switch '73 as will be more fully explained below.

It will be noted that a continuous gap-type heater is produced comprising a triangular portion integrally connected to a portion of the heater wire which is bent substantially 180 at substantially equi-distant points. This gap type heater comprises, therefore, a continuous heater wire which exhibits straight parallel portions as well as a triangular portion.

Having explained in detail the structure of my pluralcathode continuous heater-wire winder, the operation thereof will now be explained.

At the beginning of a cycle, a heater wire extends upwardly from wire feeding means 28 between feed wheels 62 and through wire guide 64 up against pin At this moment, the winding head is stationary and in the position shown in FIGS. 2 and 4, that is, the winding head is oriented vertically, the blades 5 36 and 58 are collapsed and the pin 136, and therefore the button 14-6 thereon, extends to its extreme right-hand position. operat r closes foot operated switch 185 (FIG. 13) momentarily. Clutch is energized thereby and in a small fraction of the turn of shaft 24, cam 46 lifts its follower, as shown in PEG. 8 forcing cam shaft 58 (FIGS. 6, 2 and 3) to the right. Cam shaft 53 pushes shouldered cam face 116 down causing the winding blades 86 and 88 to move laterally outward relative to blade Also, spring 1 2 is permitted to move pin 136 to the left as shown in FIG. 3. Since the heater wire is against pin 36, the heater wire is gripped between the button 146 and the end of pin 124. The winding head and button are now in the position shown in FIGS. 3 and 5 and the head is turned clockwise a fraction of a turn. The switch 1% is heid closed and cam 66, in rotation, pushes shaft 36 to the right carrying wire feeding means 23 with it. T e finger 72 no longer holds switch "76 in its open position and foot switch is released. However, due to the release of switch 76 by finger 72, switch 18% is shunted by switch 76 and clutch 38 continues to be energized, and the head 23 continues to rotate. As shaft 39 moves to the right, finger 74 rotates and does not operate switch 7-5. 66 continues to rotate and shaft 30 moves to the right carry the feeding means 25 with it. Since, as is shown in FEGS. 2 and 3, the blade :33 is shorter than blades 34 and $6, the heater wire winds only one turn on all three blades dd, and 88. At the second rotation of head 23, due to the action of cam 66, feeding means 28 has moved to the right far enough so that the heater wire is fed beyond the end of blade 88. Therefore, the heater wire misses the short blade 88 but continues to wind onto the longer blades 84 and 86. Upon completion of a predetermined number of further revolutions of head 23, the wire feeder 23 is moved to its extreme righthand position and the end of shaft 319 rides off the high part of earn 66. S rin 63 causes shaft 39 to return rapidly towards the left, and arm 72 opens switch 76 causin clutch 38 to be de-energized, stopping rotation of head 23 is a vertical position as shown in FTGS. 2 to 5. Finger 74 momentarily causes solenoid switch 78 to close thereby energizing air cylinder solenoid 132 and admitting air under high pressure to cylinder 178. Piston rod 176 goes to the right and arms 15% and 156 are rotated towards each other fast enough to cause the block 152 and the cooperating slide block 164 to strike each other. Since the heater wire between the wire clamp and the blades on the winding head, as well as the heater who between the blades and the feeding means 23 extend between the crack-off blades 1 52 and 158, the insulation is cracked off the h ater wire by the action of the crack-o5 arms. The blocks 52 and 15% continue to move and cut the heater wire as they move past each other at the end of the cracked-off portion of the heater wires. This action is illustrated in FIG. 12. The cam 46 rotates to the position where it permits spring 51 to cause bell crank to rotate counter-clockwise thereby moving cam 58 to the left. The blades 84, 86 and 8% are collapsed, that is, they take the position shown in FIGS. 2 and 4, and the button is moved to the extreme right-hand position by spring 144. The operator removes the finished inte ral series wound heaters, and the cycle is completed.

What is claimed is:

1. Apparatus for producing a continuous skip-gap heater for plural-purpose tubes from an insulated wire, comprising a winding head, means for rotating said winds,151,esv

. Z7 7 ing head about an axis therethrough, three winding lades on an end of said winding head and extending in the direction of said axis, two of said blades being longer than the third thereof, means for feeding said insulated wire to said winding head, means for moving said feeding means along the direction of said axis whereby a first portion of said wire is wound over said three blades and a further portion of said wire clears said third blade and is wound over said two longer blades, means for stopping the rotation of said winding head after a predetermined number of turns thereof, means for removing the insulation from the heater wire at a portion thereof removed from the wound portion, means for cutting said heater wire at said removed portion and means for causing relative motion of said blades towards each otner, whereby the wound heater may be removed from said blades.

2. In an apparatus for producing a continuous skipgap heater for plural-purpose tubes from a continuous wire, comprising a winding head'having an axis, three separate winding blades on said winding head and extending in a direction along said axis, one of said three blades being shorter than the other two of said blades, a source of wire, means for fastening said wire to said winding head, means for rotating said winding head about said axis, and means for moving said wire relative to said winding head along said axis-to wind said wire over said three blades for one turn of said head and for winding said wire over only said other two blades for at least an additional turn of said head. 7

3. In an apparatus for producing a continuous snipgap heater for plural-purpose tubes from a heater wire comprising, a winding head having an axis, a wire holding means on said winding head having a wire holding and a wire release position, a plurality of at least three winding blades fastened to said winding head and extending in a direction along said axis, two of said blades being moveable with resnect to a third of said blades and with respect to each other, one of said three blades being shorter than the other two thereof, means to move said wire holding means towire holding position, means to move said moveable blades to a separated position, resilient means to move said wire holding means to wire release position, resilient means to move said moveable blades to a position closer than said separated pos -on, a source of wire, means for moving said source of who and said winding head relative to one another in a direction along said axis, and means for rotating said head and said source relative to one another around said axis.

. 4. In an apparatus for producing a continuous heater for plural-purpose tubes, a winding head having an end, a wire holding means extending from said end of said winding head, said wire holding means having a w re holding and a wire release position, three winding blades 8 head, and means for causing relative movement of said source with said winding head in a direction along said axis.

6. In an apparatus for producing a continuous heater for plural-purpose tubes, a winding head having an end and having an axis extending through said end, said winding head having three blades extending from said end in a direction along said axis, two of said blades being of substantially equal length and the third thereof being shorter than said two blades, two of said blades being pivoted on said head to move towards and away from each other, means for rotating said winding head about said axis, a wire source, means for connecting a. wire from said sourceto said winding head, and means for causing relative movement of said source with said 'winding'head in a direction along said axis.

7. In an apparatus for producing a continuous heater for plural-purpose tubes, a winding head having an end and having an axis extending through said end, said winding head having three blades extending from said end in a direction along said axis, two of said blades being of substantially equal length and the third thereof being shorter than said two blades, means to rotate said head about said axis, a wire source, means for connecting a wire from said source to said head, and means for moving the wire source along the direction of said axis.

8. In an apparatus for producing a continuous heater for plural-purpose tubes, a winding head having an end and having an axis extending through said end, said winding head having three blades extending from said end in a direction along said axis, two of said blades being of substantially equal length and the third thereof being shorter than said two blades, two of said blades being pivoted on said head to move towards and away from each other, means to move said two blades about said pivots, means for rotating said head about said axis, a wire source, means for connecting a wire from said source to said head, and means for moving said wire source along the direction of said axis.

9. In an apparatus for producing a continuous heater for plural-purpose tubes, a winding head having an end and having an axis extending through said end, said extending from said end of said winding head and in a a direction along an axis, one of said blades being shorter than the other two thereof, two of said blades being moveable towards and away from the third of said blades,

7 relative to one another around said axis.

5.111 an apparatus for producing a cont'muous heater for plural-purpose tubes, a winding head having an end and having an axis extending through said end; said winding head having three blades extending from said endina direction along said axis, two of said blades being of, substantially equallength and the third thereof being shorter than saidtwo blades, means for rotating winding head having three blades extending from, said end in a direction from said ax s, two of said blades being of substantially equal length and the third thereof being shorter than said two blades, two of said blades being pivoted on said head to move towardsand away from each other, means for rotating said head and including a shaft extending in the direction of said axis and fastened to said head, means to move said two blades about their pivots, said means to move said two blades and said means for rotating said head being concentrically arranged, a wire source, means for connecting a wire from said source to said head, and means for moving said source along the direction of said axis.

' 10. A winding head for a skip-gap heater spade-winding apparatus comprising a housing adapted to be secured to a hollow shaft having a moveable cam rod slidably sup-' ment thereof upon movement of said cam shaft whereby said winding head about said axis, a Wire source, means for connecting a wire from said source to said winding:

said blades are moved toward and fromieach other to permit winding and stripping of a skip-gap heater, means for rotating said head about said axis, a wire source, means for connecting a wire from said source to said head,and means for moving said source relative to said head along vthe direction of said axis. 7

ll. A gap-type heater spade-winding appa atus comprising a frame, a hollow shaft rotatably mounted on said frame, a Winding head secured to one end of said hollow shaft, said winding head comprising a housing, a first blade fixed to said housing, a second blade pivotally mounted on said housing and oppositely disposed to said fixed blade, a third blade rotatably mounted on said housing and rotatable toward and from said fixed blade and said pivoted blade, said third blade being shorter than said first and second blades, said three blades extending in a direction along an axis, cam means associated with said pivoted blade and said rotatable blade, a cam shaft slidably supported within said hollow shaft, and contacting said cam means, a rotatable cam operably connected with said hollow shaft to be rotated thereby, means connected between said cam and said cam shaft for moving said cam shaft to cause said blades to have relative movement with respect to each other for moving said blades toward and from each other, means for rotating said head about said axis, a wire source, means for connecting a wire from said source to said head, and means for moving said source relative to said head along the direction of said axis.

12. A gap-type heater spade-winding apparatus comprising a frame, a hollow shaft rotatably mounted on said frame, a winding head secured to one end of said hollow shaft, said winding head comprising a housing, a first blade fixed to said housing, a second blade pivotally mounted on said housing and oppositely disposed to said fixed blade, means for biasing said second blade toward said first blade, a third blade rotatably mounted on said housing and rotatable toward and from said fixed blade and said pivoted blade, said third blade being shorter than said first and second blades, said three blades extending in a direction along an axis, cam means associated with said pivoted blade and said rotatable blade, a cam shaft slidably supported within said hollow shaft and operatively associated with said cam means, means for sliding said cam shaft to cause said blades to have relative movement with respect to each other for moving said blades toward and from each other, means for rotating said head about said axis, a wire source, means for connecting a wire from said source to said head, and means for moving said source relative to said head along the direction of said axis.

13. A gap-type heater spade winding apparatus comprising a frame, a hollow shaft rotatably mounted on said frame, a winding head secured to one end of said hollow shaft, said winding head comprising a housing, a first blade fixed to said housing, a second blade pivotally mounted on said housing and oppositely disposed to said fixed blade, means for biasing said second blade toward said first blade, a third blade rotatably mounted on said housing and rotatable toward and from said fixed blade and said pivoted blade, said third blade being shorter than said first and second blades, said three blades extending in a direction along an axis, cam means associated with said pivoted blade and said rotatable blade, a cam shaft slidably supported within said hollow shaft, and operatively associated with said cam means, a rotatable cam operably connected with said hollow shaft to be rotated thereby, means connected between said cam and said cam shaft for moving said cam shaft to cause said blades to have relative movement with respect to each other for moving said blades toward and from each other, means for rotating said head about said axis, a wire source, means for connecting a wire from said source to said head, and means for moving said source relative to said head along the direction of said axis.

14. Apparatus for producing a heater comprising a winding head having an axis, three separate winding blades on said winding head and extending in a direction along said axis, one of said three blades being shorter than the other two of said blades, guide means for guiding Wire towards said winding head, means for rotating said winding head, and means for advancing said wire guide along said direction to wind said wire over said three blades for at least one turn of said head and for winding said wire only over said other two blades for at least an additional turn of said head.

References Cited in the file of this patent UNITED STATES PATENTS 1,013,572 Suman Jan. 2, 1912 1,265,575 Wright May 7, 1918 2,187,267 Galligan Jan. 16, 1940 2,380,320 La France July 10, 1945 2,448,916 Schneider et a1 Sept. 7, 1948 2,736,345 Caldwell Feb. 28, 1956 2,782,809 Smallridge Feb. 26, 1957 

1. APPARATUS FOR PRODUCING A CONTINUOUS SKIP-GAP HEATER FOR PLURAL-PURPOSE TUBES FROM AN INSULATED WIRE, COMPRISING A WINDING HEAD, MEANS FOR ROTATING SAID WINDING HEAD ABOUT AN AXIS THERETHROUGH, THREE WINDING BLADES ON AN END OF SAID WINDING HEAD AND EXTENDING IN THE DIRECTION OF SAID AXIS, TWO OF SAID BLADES BEING LONGER THAN THE THIRD THEREOF, MEANS FOR FEEDING SAID INSULATED WIRE TO SAID WINDING HEAD, MEANS FOR MOVING SAID FEEDING MEANS ALONG THE DIRECTION OF SAID AXIS WHEREBY A FIRST PORTION OF SAID WIRE IS WOUND OVER SAID THREE BLADES AND A FURTHER PORTION OF SAID WIRE CLEARS SAID THIRD BLADE AND IS WOUND OVER SAID TWO LONGER BLADES, MEANS FOR STOPPING THE ROTATION OF SAID WINDING HEAD AFTER A PREDETERMINED NUMBER OF TURNS THEREOF, MEANS FOR REMOVING THE INSULATION FROM THE HEATER WIRE AT A PORTION THEREOF REMOVED FROM THE WOUND PORTION, MEANS FOR CUTTING SAID HEATER WIRE AT SAID REMOVED PORTION AND MEANS FOR CAUSING RELATIVE MOTION OF SAID BLADES TOWARDS EACH OTHER, WHEREBY THE WOUND HEATER MAY BE REMOVED FROM SAID BLADES. 